Semiconductor packages

ABSTRACT

A semiconductor package includes a plurality of semiconductor chips. At least one of the semiconductor chips includes a semiconductor substrate including a semiconductor layer and a passivation layer having a third surface, a backside pad on the third surface, and a through-via penetrating through the semiconductor substrate. The backside pad includes an electrode pad portion, on the third surface, and a dam structure protruding on one side of the electrode pad portion and surrounding a side surface of the through-via. The dam structure is spaced apart from the side surface of the through-via.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of priority to Korean PatentApplication No. 10-2020-0125675, filed on Sep. 28, 2020 in the KoreanIntellectual Property Office, the disclosure of which is incorporatedherein by reference in its entirety.

BACKGROUND

The present disclosure relates to semiconductor packages. It may bebeneficial for semiconductor packages mounted on electronic devices tobe compact, to have high performance, and to have high capacity. Inorder to implement this, research and development (R&D) of asemiconductor package, in which semiconductor chips havingthrough-silicon vias (TSVs) are vertically stacked, is being conducted.

SUMMARY

Example embodiments provide a semiconductor package having improvedthrough-via reliability.

According to an example embodiment, a semiconductor package includes aplurality of semiconductor chips electrically connected to each otherand stacked in a first direction. At least one of the plurality ofsemiconductor chips includes a semiconductor substrate including asemiconductor layer, having a first surface and a second surface thatare opposite each other, and a passivation layer on the first surfaceand having a third layer that is opposite the first surface, a circuitstructure on the second surface, a frontside pad on the circuitstructure, a backside pad on the third surface, and a through-via in thesemiconductor substrate and extending between the second surface and thethird surface to be electrically connected to the backside pad and thefrontside pad. The backside pad includes an electrode pad portion, onthe third surface, and a dam structure protruding toward the firstsurface on one side of the electrode pad portion and surrounding a sidesurface of the through-via. The dam structure is spaced apart from theside surface of the through-via.

According to an example embodiment, a semiconductor package includes atleast one semiconductor chip. The at least one semiconductor chip has anactive surface and an inactive surface that are opposite each other andincludes a backside pad on the inactive surface, a frontside pad on theactive surface, and a through-via electrically connecting the backsidepad and the frontside pad to each other. The backside dam includes anelectrode pad portion and a dam structure that extends in a firstdirection from the electrode pad portion toward the active surface andsurrounds the through-via. A ratio of a width of the backside pad in asecond direction, horizontal to the active surface, to a width of thethrough-via in the second direction is within a range of about 5:1 toabout 3:1. The dam structure is spaced apart from a side surface of thethrough-via.

According to an example embodiment, a semiconductor package includes: afirst semiconductor chip including a first semiconductor layer having afirst surface and a second surface that are opposite each other, apassivation layer having a third surface that is opposite the firstsurface and a trench that is in the third surface, a through-viapenetrating the semiconductor layer and the passivation layer, and abackside pad on the third surface and electrically connected to thethrough-via; a second semiconductor chip including a frontside pad andon the first semiconductor chip in such a manner that the frontside padfaces the backside pad; and a connection bump electrically connectingthe backside pad and the frontside pad to each other. The trench isspaced apart from the through-via in a first direction, horizontal tothe third surface. A spacing distance between the trench and thethrough-via is within a range of about 2 micrometers (μm) to about 5 μm.A ratio of a depth of the trench in a second direction, perpendicular tothe third surface, to a maximum distance between the third surface andthe first surface is about 0.5:1 to about 0.8:1. The backside padincludes a dam structure in the trench.

BRIEF DESCRIPTION OF DRAWINGS

The above and other aspects, features, and advantages of the presentdisclosure will be more clearly understood from the following detaileddescription, taken in conjunction with the accompanying drawings.

FIG. 1 is an exploded perspective view of a semiconductor packageaccording to an example embodiment.

FIG. 2 is a cross-sectional view taken along line I-I′ of FIG. 1 .

FIGS. 3A and 3B are perspective views of selected components of FIG. 2 .

FIGS. 4A and 4B are partially enlarged views illustrating propagationaspects of cracking around a through-via before and after applying a damstructure according to the present disclosure.

FIGS. 5A to 5H are schematic cross-sectional views illustrating a methodof manufacturing the semiconductor package illustrated in FIG. 2 .

FIG. 6 is a cross-sectional view of a semiconductor package according toan example embodiment.

FIGS. 7A and 7B are perspective views of selected components of FIG. 6 .

FIGS. 8A and 8B are cross-sectional views illustrating modified examplesof selected components in a portion corresponding to region “A” of FIG.6 .

FIG. 9 is a cross-sectional view of a semiconductor package according toan example embodiment.

FIG. 10 is a perspective view of selected components of FIG. 9 .

FIG. 11 is a cross-sectional view of a semiconductor package accordingto an example embodiment.

FIG. 12 is a cross-sectional view of a semiconductor package accordingto an example embodiment.

FIG. 13 is a cross-sectional view of a semiconductor package accordingto an example embodiment.

FIG. 14 is a cross-sectional view of a semiconductor package accordingto an example embodiment.

FIG. 15 is a cross-sectional view of a semiconductor package accordingto an example embodiment.

DETAILED DESCRIPTION

Hereinafter, example embodiments will be described with reference to theaccompanying drawings.

FIG. 1 is an exploded perspective view of a semiconductor package 1000 aaccording to an example embodiment, FIG. 2 is a cross-sectional viewtaken along line I-I′ of FIG. 1 , FIGS. 3A and 3B are perspective viewsof selected components of FIG. 2 , and FIGS. 4A and 4B are partiallyenlarged views illustrating propagation aspects of cracking CR around athrough-via 140 before and after applying a dam structure according tothe present disclosure.

Referring to FIG. 1 , the semiconductor package 1000 a may include aplurality of semiconductor chips 100, 200, . . . , and n electricallyconnected to each other and stacked in a vertical direction (a Z-axisdirection). Each of the semiconductor chips 100, 200, . . . , and n mayinclude a logic chip or a memory chip. For example, the plurality ofsemiconductor chips 100, 200, . . . , and n may include a logic chipsuch as a central processing unit (CPU), a graphics processing unit(GPU), a field programmable gate array (FPGA), a digital signalprocessor (DSP), a cryptographic processor, a microprocessor, amicrocontroller, an analog-digital converter, or an application-specificintegrated circuit (ASIC), or a volatile memory chip such as a dynamicrandom access memory (DRAM) or a static random access memory (SRAM), ora nonvolatile memory chip such as a phase-change random access memory(PRAM), a magnetic random access memory (MRAM), a resistive randomaccess memory (RRAM), or a flash memory. All of the semiconductor chips100, 200, . . . , and n may be the same type of memory chip.Alternatively, some of the semiconductor chips 100, 200, . . . , and nmay be memory chips and some thereof may be logic chips. The number ofthe plurality of semiconductor chips 100, 200, . . . , and n is notnecessarily limited, and two, four, eight, sixteen, or moresemiconductor chips may be stacked. Among the semiconductor chips 100,200, . . . , and n, the lowermost semiconductor chip n may include onlya frontside pad Pn without having a through-via. The lowermostsemiconductor chip n may correspond to an uppermost stackedsemiconductor chip of FIG. 13 to be described later. Accordingly, sincea connection terminal on a frontside is unnecessary, the lowermostsemiconductor chip n may not have a through-via.

The first semiconductor chip 100 and the second semiconductor chip 200,illustrated in the drawings, may include frontside pads 150 and 250 andbackside pads 160 and 260, and through-vias 140 and 240 for electricalconnection therebetween. For example, the first backside pad 160 and thesecond frontside pad 250, corresponding to each other, may beelectrically connected to each other through a connection member (forexample, a solder ball). The second frontside pad 250 may be aconnection pad of a bare chip or a metal bump structure formed on aconnection pad of a bare chip. In an example embodiment, the pluralityof semiconductor chips 100, 200, . . . , and n may have substantiallythe same technical features. Therefore, referring to FIG. 2 togetherwith FIG. 1 , features of the semiconductor package 1000 a according toan example embodiment will be described while focusing on the firstsemiconductor chip 100. FIG. 2 illustrates a cross section of the firstsemiconductor chip 100 taken along line I-I′ of FIG. 1 .

Referring to FIG. 2 together with FIG. 1 , the semiconductor package1000 a according to an example embodiment may include a semiconductorchip 100 including a semiconductor substrate 110, a first circuitstructure 120 and a second circuit structure 130 (hereinafter, thestructures 120 and 130 may be collectively or individually referred toas “circuit structure”), a through-via 140, a frontside pad 150, and abackside pad 160. Similarly, a semiconductor chip 200 may include asemiconductor substrate 210 and circuit structures 220 and 230, as wellas a through-via 240, a frontside pad 250, and a backside pad 260.

The semiconductor substrate 110 may include a semiconductor layer 111having a first surface 111S1 and a second surface 111S2 that areopposite (e.g., disposed to oppose) each other, a plurality ofconductive regions 112 and isolation regions 113 formed in thesemiconductor layer, and a passivation layer 114 disposed on the firstsurface 111S1 and having a third surface 114S disposed to oppose thefirst surface 111S1. The semiconductor substrate 110 may be asemiconductor wafer. The semiconductor layer 111 may include asemiconductor element such as silicon or germanium, or a compoundsemiconductor such as silicon carbide (SiC), gallium arsenide (GaAs),indium arsenide (InAs), or indium phosphide (InP). The conductive region112 may be, for example, a well doped with impurities or a structuredoped with impurities. The isolation region 113 may be a deviceisolation structure having a shallow trench isolation (STI) structure,and may include silicon oxide.

The passivation layer 114 may be an insulating layer including siliconoxide, silicon nitride, a polymer, or a combination thereof. Thepassivation layer 114 may be disposed between the backside pad 160 andthe semiconductor layer 111 and may surround a portion of a side surfaceof the through-via 140. The passivation layer 114 may be formed by achemical vapor deposition (CVD) process. A thickness 114 h of thepassivation layer 114 is not necessarily limited, but may be about 2 μmor more to protect semiconductor chips, through-vias, and the like. Forexample, the thickness 114 h of the passivation layer 114 may be withinthe range of about 2 μm to about 5 μm.

The passivation layer 114 may have a trench T1 formed by recessing aportion of the third surface 114S. The trench T1 may provide a space inwhich a dam structure 163 of the backside pad 160 to be described lateris formed (e.g., where the dam structure 163 penetrates the thirdsurface 114S such that the dam structure 163 protrudes beyond the thirdsurface 114S toward the first surface 111S1 without contacting the firstsurface 111S1). Therefore, the trench T1 may be spaced apart from thethrough-via 140 in a horizontal direction (an X-axis direction that maybe perpendicular to the Z-axis direction), horizontal to a third surface114S, to secure a sufficient spacing distance between the through-via140 and the dam structure 163 including the conductive material. Forexample, a spacing distance dl between the trench T1 and the through-via140 may be within the range of about 2 μm to about 5 μm. When thespacing distance dl between the trench T1 and the through-via 140 isless than about 2 μm, an electrical failure may occur between the damstructure 163 and the through-via 140 or cracking propagating within thepassivation layer 114 may bypass the dam structure 163 and then reachthe through-via 140. When the spacing distance dl between the trench T1and the through-via 140 is greater than about 5 μm, the cracking maybypass the dam structure 163 and then reach the through-via 140 in asimilar manner. In addition, the dam structure 163 may be required tohave a certain level of height so as to prevent/impede the propagationof the cracking. Accordingly, the trench T1 may have a depth Th1 of apredetermined level or more in a vertical direction (a Z-axis direction)to cover a portion of a side surface of the through-via 140. Forexample, a ratio of the depth Th1 to a maximum distance 114 h betweenthe third surface 114S and a first surface 111S1 may be within the rangeof about 0.5:1 to about 0.8:1. When a ratio of the depth Th1 of thetrench T1 to a maximum thickness 114 h of the passivation layer 114 isless than 0.5:1, a cracking prevention/reduction effect may beinsignificant. When the ratio of the depth Th1 of the trench T1 to themaximum thickness 114 h of the passivation layer 114 is greater than0.8:1, diffusion may occur between the dam structure 163 and thesemiconductor layer 111.

The circuit structures 120 and 130 may include a first circuit structure120 and a second circuit structure 130 stacked on the second surface111S2 of the semiconductor layer 111. The first circuit structure 120may include a first interlayer insulating layer 121, a plurality ofindividual devices 122, and a first wiring structure 123. The firstinterlayer insulating layer 121 may be disposed on an upper surface ofthe semiconductor substrate 110 or on an upper surface 111S2 of thesemiconductor layer 111, and may include silicon oxide or siliconnitride. The plurality of individual devices 122 may be combined witheach other to constitute an integrated circuit (IC). The plurality ofindividual devices 122 may include various microelectronic devices, forexample, a metal-oxide-semiconductor field effect transistor (MOSFET), asystem large scale integration (LSI) device, and amicro-electro-mechanical system (MEMS), an active device, a passivedevice, and the like. The plurality of individual devices 122 mayinclude a gate structure disposed around a conductive region 112. Thefirst wiring structure 123 may include at least one layer of wiringlines extending in a horizontal direction (an X-axis direction) and atleast one layer of wiring vias extending in a vertical direction (aY-axis direction), and may be electrically connected to a plurality ofindividual devices 122. The first wiring structure 123 may have amultilayer structure including a plurality of wiring lines and aplurality of wiring vias. As illustrated in the drawings, the wiringline of the first wiring structure 123 may be in direct contact with thethrough-via 140. Alternatively, the wiring line of the first wiringstructure 123 may be electrically connected to the through-via 140through the wiring via. The first wiring structure 123 may include, forexample, a metal wiring layer (or a metal via layer), including aluminum(Al), gold (Au), cobalt (Co), copper (Cu), nickel (Ni), lead (Pb),tantalum (Ta), tellurium (Te), titanium (Ti), tungsten (W), orcombinations thereof, and a barrier layer disposed between the metalwiring layer and the interlayer insulating layer 121 and includingtitanium (Ti), titanium nitride (TiN), tantalum (Ta), or tantalumnitride (TaN). It will be understood that, in addition to the firstwiring structure 123 illustrated in the drawings, a first wiringstructure connected to the individual devices 122 is present but omittedfrom view in FIG. 2 for simplicity of illustration.

The second circuit structure 130 may include a second interlayerinsulating layer 131, disposed on the first circuit structure 120, and asecond wiring structure 133 electrically connected to the first wiringstructure 123. The second interlayer insulating layer 131 may bedisposed on an upper surface of the first circuit structure 120 and mayinclude silicon oxide or silicon nitride. Similarly to the first wiringstructure 123, the second wiring structure 133 may include at least onelayer of wiring lines and at least one layer of wiring vias. The secondwiring structure 133 may also be formed to have a multilayer wiringstructure including a plurality of wiring lines and a plurality ofwiring vias. It will be understood that, in addition to the secondwiring structure 133 illustrated in the drawings, a second wiringstructure is present (but omitted from view in FIG. 2 for simplicity ofillustration) for connecting the individual devices 122 in the firstinterlayer insulating layer 121 to each other or for connecting theindividual devices 122 to another wiring.

The through-via 140 may extend through at least a portion of thesemiconductor chip 100 (FIG. 1 ) to electrically connect the frontsidepad 150 and the backside pad 160 to each other. For example, thethrough-via 140 may extend through the semiconductor substrate 110 inthe vertical direction (the Z-axis direction) to be in contact with thebackside pad 160, and may be electrically connected to the frontside pad150 through the first and second wiring structures 123 and 133. Thethrough-via 140 may include a metal plug 142, extending between upperand lower surfaces of the semiconductor chip 100 and/or between thefrontside pad 150 and the backside pad 160, and a barrier layer 141surrounding the metal plug 142. The metal plug 142 may include a metal,for example, tungsten (W), titanium (Ti), aluminum (Al), or copper (Cu).The metal plug 142 may be formed by a plating process, a physical vapordeposition (PVD) process, or a chemical vapor deposition (CVD) process.The barrier layer 141 may include a metal compound such as tungstennitride (WN), titanium nitride (TiN), or tantalum nitride (TaN). Thebarrier layer 141 may be formed by a PVD process or a CVD process. A viainsulating layer may be formed on a side surface of the through-via 140.The via insulating layer may have a single-layer structure or amultilayer layer structure. The via insulating layer may include siliconoxide, silicon oxynitride, silicon nitride, a polymer, or combinationsthereof.

The frontside pad 150 and the backside pad 160 may be disposed onopposite surfaces of a semiconductor chip (e.g., the chip 100 in FIG. 1), respectively. For example, the frontside pad 150 may be disposed onan active surface of a semiconductor chip in which the circuitstructures 120 and 130 are formed. The backside pad 160 may be disposedon an inactive surface opposing the active surface. The frontside pad150 and the backside pad 160 may be electrically connected to each otherthrough the through-via 140 and the wiring structures 123 and 133. Eachof the frontside pad 150 and the backside pad 160 may have a ball shapeor a post shape, other than a pad shape. The frontside pad 150 and thebackside pad 160 may include a metallic material such as copper (Cu),aluminum (Al), nickel (Ni), silver (Ag), gold (Au), tin (Sn), lead (Pb),titanium (Ti), or the like.

The backside pad 160 may be disposed on a rear surface (or an inactivesurface) of the semiconductor chip or on the third surface 114S of thepassivation layer 114, and may include a metal layer 161, an electrodepad portion 162, and a dam structure 163. The metal layer 161 may beconformally formed along a certain region of the surface 114S of thepassivation layer 114 and an internal surface of the trench T1. Themetal layer 161 may be disposed between the dam structure 163 and thepassivation layer 114, between the electrode pad portion 162 and thepassivation layer 114, and between the electrode pad portion 162 and thethrough-via 140. The metal layer 161 may cover upper and side surfacesof the dam structure 163 and an upper surface of the electrode padportion 162. The metal layer 161 may be a seed layer of the electrodepad portion 162 and the dam structure 163, and may include at least onemetal selected from the group consisting of titanium (Ti), copper (Cu),cobalt (Co), tungsten (W), and palladium (Pd), and chromium (Cr). Athickness of the metal layer 161 may be within the range of, forexample, about 0.05 μm and about 3 μm. The metal layer 161 may be formedthrough a sputtering process. The electrode pad portion 162 may includea portion, overlapping the through-via 140 in the vertical direction(the Z-axis direction), and a portion extending from the overlappingportion in the horizontal direction (the X-axis direction). Theelectrode pad portion 162 may include at least one metal selected fromthe group consisting of copper (Cu), nickel (Ni), gold (Au), tantalum(Ta), and tungsten (W). The electrode pad portion 162 may be formed byan electroplating process. The dam structure 163 may be embedded in thetrench T1 of the passivation layer 114 and may be formed to beintegrated with the electrode pad portion 162. Accordingly, a boundarybetween the electrode pad portion 162 and the dam structure 163 may notbe apparent. Rather, the dam structure 163 may be avertically-protruding portion of the electrode pad portion 162. Aboundary (dashed lines) between the metal pad portion 162 and the damstructure 163, illustrated in the drawings, may be an imaginary lineadded for easy understanding of structural features of the presentdisclosure.

Hereinafter, the dam structure 163 will be described in detail withreference to FIGS. 3A and 3B together. FIGS. 3A and 3B are perspectiveviews illustrating shapes of the electrode pad portion 162, the damstructure 163, and the through-via 140 in an example embodiment. FIGS.3A and 3B are perspective views illustrating different modified examplesof the shape of the dam structure 163, respectively.

Referring to FIG. 2 together with FIG. 3A, the dam structure 163 mayprotrude from one side of the electrode pad portion 162 toward the firstsurface 111S1 or the active surface of the semiconductor chip, and maysurround a side surface of the through-via 140. As used herein, theterms “surround” and “surrounding” do not require that a first elementcontinuously covers an entire surface of a second element in a verticaland/or circumferential direction. Rather, these terms refer to aborder/perimeter that the first element forms either continuously ordiscontinuously around the surface of the second element. In someembodiments, the dam structure 163 may have a ring shape continuouslysurrounding the through-via 140. For example, the dam structure 163 maycontinuously surround a circumference of a portion (e.g., an endportion) of the through-via 140. The dam structure 163 may surround thethrough-via 140 while having various shapes such as a triangular shapeor a rectangular shape, other than a circular shape illustrated in FIG.3A. The dam structure 163 may have a certain level of spacing distancefrom the through-via 140 and a certain level of height, as compared witha thickness of the passivation layer 114, to prevent/impede crackingfrom propagating from outside of the backside pad 160 to the backsidepad 160 and to prevent/impede cracking, propagating upwardly of thebackside pad 160, from reaching the through-via 140.

For example, the dam structure 163 may be spaced apart from thethrough-via 140 in first and second directions (the X-axis and Y-axisdirections). The dam structure 163 may be spaced apart from thethrough-via 140 by a spacing distance dl between the trench T1 and thethrough-via 140. Substantially, the dam structure 163, spaced apart fromthe through-via 140 by the spacing distance dl between the trench T1 andthe through-via 140, may be further spaced apart therefrom by athickness of the metal layer 161 surrounding the side surface of the damstructure 163. However, since both the dam structure 163 and the metallayer 161 include a conductive material, the dam structure 163 may beconsidered to be spaced apart from the through-via 140 by the spacingdistance dl between the trench T1 and the through-via 140, irrespectiveof the thickness of the metal layer 161. Accordingly, the dam structure163 may be spaced apart from the through-via 140 by about 2 μm or more.For example, the spacing distance between the dam structure 163 and thethrough-via 140 may be within the range of about 2 μm to about 5 μm.When the spacing distance between the dam structure 163 and thethrough-via 140 is less than about 2 μm, an electrical failure may occurbetween the dam structure 163 and the through-via 140 or cracking,propagating within the passivation layer 114, may bypass the damstructure 163 and then reach the through-via 140. When the spacingdistance between the dam structure 163 and the through-via 140 isgreater than about 5 μm, the cracking may bypass the dam structure 163and then reach the through-via 140 in a similar manner.

In addition, the dam structure 163 may be disposed within a width of thebackside pad 160 in horizontal directions (the X-axis and Y-axisdirections) to effectively prevent/impede cracking from propagatingupwardly of the backside pad 160 from outside of the backside pad 160.In addition, the dam structure 163 may be spaced apart from the sidesurface of the through-via 140 and may have one side surface coplanarwith or spaced apart from a side surface 162SS of the electrode padportion 162. For example, the backside pad 160 or the electrode padportion 162 thereof may have a width 160 w having a ratio ranging from5:1 to 3:1 in the first direction (the X direction) relative to a width140 w of the through-via 140, and the dam structure 163 may be disposedwithin the width 160 w of the backside pad 160 or the electrode padportion 162 thereof. In this case, an external side surface of the damstructure 163 may be spaced apart from or coplanar with the externalside surface 162SS of the electrode pad portion 162. The external sidesurface of the dam structure 163 may be defined as a side surface of thedam structure disposed to oppose an internal side surface of the damstructure 163, facing the through-via 140, on the drawings. Therefore,the dam structure 163 may be formed in a location overlapping theelectrode pad portion 162 in the vertical direction (the Z-axisdirection). When the dam structure 163 protrudes outwardly of thebackside pad 160 to increase a distance to the through-via 140, densityof the dam structure 163 around the through-via 140 may be reduced toresult in an insignificant cracking prevention/reduction effect.

The dam structure 163 may have a height 163 h of a certain level or morein the first direction (the Z-axis direction). When the metal layer 161is conformally formed on an upper surface of the dam structure 163 andan upper surface of the electrode pad portion 162, the height 163 h ofthe dam structure 163 may be substantially the same as the depth Th1 ofthe trench T1. For example, a ratio of the height 163 h of the damstructure 163 in the first direction (the Z-axis direction) to a maximumthickness 114 h of the passivation layer 114 may be within the range ofabout 0.5:1 to about 0.8:1.

Referring to FIG. 3B, in a modified example, the dam structure 163 mayinclude a plurality of separation walls 163 a and 163 b discontinuouslysurrounding the through-via 140. Each of the separation walls 163 a and163 b may satisfy conditions for the spacing distance to the through-via140 and the thickness of the passivation layer 114. A spacing distance wbetween the separation walls 163 a and 163 b may be smaller than aspacing distance between the through-via 140 and the separation walls163 a and 163 b. When the spacing distance w between the separationwalls 163 a and 163 b is greater than the spacing distance between thethrough-via 140 and the separation walls 163 a and 163 b, it may bedifficult to effectively prevent/impede propagation of cracking.

Hereinafter, a cracking propagation prevention/reduction effect,obtained by the dam structure 163 in the package according to an exampleembodiment, will be described with reference to FIGS. 4A and 4B. FIGS.4A and 4B are partially enlarged views illustrating a state in which thefirst and second semiconductor chips 100 and 200 of FIG. 1 are bonded bya connection member 30. FIG. 4A illustrates a propagation aspect ofcracking CR on a backside pad 160′ before (i.e., without) applying thedam structure 163 according to an example embodiment. FIG. 4Billustrates a propagation aspect of cracking CR on a backside pad 160after applying the dam structure 163 according to an example embodiment.In FIGS. 4A and 4B, a frontside pad 250 is illustrated as having asimilar size as a backside pad 160/160′. The frontside pad 250,illustrated in FIGS. 4A and 4B, may be a connection pad of a bare chipor a bump structure formed on the connection pad, for example, a metalpillar.

Referring to FIG. 4A, when a plurality of semiconductor chips 100 and200 are stacked, cracking CR may occur in a bonding portion between abackside pad and a frontside pad on which stress is structurallyconcentrated. For example, when the first semiconductor chip 100 and thesecond semiconductor chip 200 are bonded, stress may be concentrated ona bonding portion between the first backside pad 160′ and the secondfrontside pad 250 and cracking CR may occur in the passivation layer 114having relatively low rigidity. The cracking CR may propagate to thefirst backside pad 160′ within the passivation layer 114 to damage eventhe through-via 140.

Referring to FIG. 4B, in an example embodiment, a dam structure 163,protruding toward the passivation layer 114 to surround a side surfaceof a through-via 140, may prevent/impede cracking CR from propagating tothe through-via 140. For example, the first backside pad 160 may includea dam structure 163 surrounding a lower portion of the side surface ofthe through-via 140. The dam structure 163 may have a heightcorresponding to 50% to 80% of a thickness of the passivation layer 114.The dam structure 163 may prevent/impede the cracking CR frompropagating upwardly of the first backside pad 160 from outside of thefirst backside pad 160. According to an example embodiment, since anadditional structure (for example, an under-bump metallization (UBM)) isnot formed on the backside pad 160, reliability of connection betweenthe through-via 140 and the backside pad 160 may be secured withoutincreasing a thickness of a package in which a plurality of chips arestacked. Moreover, the electrode pad portion 162 and the dam structure163 may be simultaneously formed by a plating process, so that a damstructure 163 for cracking prevention/reduction may be formed without anadditional burdensome process, other than a simple etching process inwhich a trench is formed in the passivation layer 114.

FIGS. 5A to 5H are schematic cross-sectional views illustrating a methodof manufacturing the semiconductor package illustrated in FIG. 2 .

Referring to FIG. 5A, a semiconductor substrate 110′, in which circuitstructures 120 and 130 are formed, may be attached to a carrier 1including a support substrate 2 and an adhesive layer 3. Thesemiconductor substrate 110′ may be in a state in which it includes onlya semiconductor layer 111′ before a polishing process. The semiconductorlayer 111′ may be formed to fully cover one end of the through-via 140.The circuit structures 120 and 130 may include interlayer insulatinglayers 121 and 131 and wiring structures 123 and 133. The semiconductorsubstrate 110′ may be disposed on the carrier 1 such that the circuitstructures 120 and 130 face an adhesive layer 3. The frontside pad 150on the circuit structures 120 and 130 may be embedded in the adhesivelayer 3. When an upper surface of the semiconductor substrate 110′ orthe semiconductor layer 111′ thereof (as shown in the drawing) ispolished, the support substrate 2 may relieve mechanical stress actingon the semiconductor substrate 110′ and may prevent/reduce warpage ofthe semiconductor substrate 110′ thinned after the polishing process.The support substrate 2 may be a glass substrate or a resin substrate.As the adhesive layer 3, an ultraviolet adhesive, a thermoplasticadhesive, or an adhesive tape may be used.

Referring to FIG. 5B, a portion of the semiconductor layer 111′ of FIG.5A may be removed to expose a portion of the through-via 140. Thethrough-via 140 may protrude upwardly of a first surface 111S1 of thesemiconductor layer 111 having a certain removed region. Thesemiconductor layer 111, having a certain removed region, may be thinnedto have a thickness of about 10 μm to 100 μm. The semiconductor layer111′ of FIG. 5A may be removed by a CHIP process or/and an etch-backprocess.

Referring to FIG. 5C, a passivation layer 114′ may be formed on thefirst surface 111S1 of the semiconductor layer 111. The passivationlayer 114′ may be formed to fully cover an upper surface of thethrough-via 140 (as shown in the drawing). A portion of the through-via140 may be removed together with a portion of the passivation layer 114′in a subsequent process. The passivation layer 114′ may be a siliconoxide layer, a silicon nitride layer, a polymer layer, or an insulatinglayer including combinations thereof. The passivation layer 114′ may beformed using an oxidation process or a deposition process, for example.

Referring to FIG. 5D, a trench T1 may be formed in an upper surface ofthe passivation layer 114′. The trench T1 may be formed to be recessedalong the periphery of the through-via 140. The trench T1 may be formedby etching the upper surface of the passivation layer 114′. For example,when the passivation layer 114′ comprises a silicon oxide layer, atrench T1 may be formed using a solution or gas for etching a maskpattern and the silicon oxide layer. The trench T1 may be formed to havea depth of 50% to 80% of a thickness of the final passivation layer 114′in consideration of a polishing process of the passivation layer 114′ tobe described later. The trench T1 may be spaced apart from thethrough-via 140 by about 2 μm or more. When the spacing distance to thethrough-via 140 is maintained to be about 2 μm or more, a width of thetrench T1 is not necessarily limited.

Referring to FIG. 5E, a portion of the passivation layer 114′ of FIG. 5Dmay be removed to form a passivation layer 114. A thickness of thepassivation layer 114 may be within the range of about 2 μm to about 5μm. The passivation layer 114 may be removed by an etch-back process. Asurface of a metal plug 142 of the through-via 140 may be exposedadjacent the third surface 114S of the passivation layer 114. Theexposed surface of the metal plug 142 may be substantially coplanar withthe third surface 114S of the passivation layer 114. A ratio of athickness of a residual trench T1 to a maximum thickness of thepassivation layer 114 may be within the range of 0.5:1 to 0.8:1.

Referring to FIG. 5F, a metal layer 161 may be formed on exposedsurfaces of the passivation layer 114, the trench T1, and thethrough-via 140. The metal layer 161 may be conformally formed along thethird surface 114S and a wall surface of the trench T1. The metal layer161 may include at least one metal selected from the group consisting oftitanium (Ti), copper (Cu), cobalt (Co), tungsten (W), palladium (Pd),and chromium (Cr). A thickness of the metal layer 161 may be within therange of, for example, about 0.05 μm to about 3 μm. The metal layer 161may be formed by a sputtering process.

Referring to FIG. 5G, a mask pattern PR may be formed on the metal layer161. The mask pattern PR may be a patterned photoresist. The maskpattern PR may be formed to expose both the through-via 140 and thetrench T1. A ratio of a width of an opening H of the mask pattern PR,exposing the through-via 140 and the trench T1, to a width of thethrough-via 140 may be within the range of 5:1 to 3:1. Then, the openingH may be filled with a metallic material to form a backside pad. Theopening H may be formed by exposure and development processes.

Referring to FIG. 5H, after a backside pad 160 is formed, a portion ofthe mask pattern PR and a portion of the metal layer 161 of FIG. 5G maybe removed. The backside pad 160 may be formed by a plating processusing the metal layer 161, exposed through the opening H of FIG. 5G, asa seed layer. The backside pad 160 may include a dam structure 163,filling the trench T1, and an electrode pad portion 162 covering thethrough-via 140 and the dam structure 163. The electrode pad portion 162and the dam structure 163 may include at least one metal selected formthe group consisting of copper (Cu), nickel (Ni), gold (Au), tantalum(Ta), and tungsten (W). The electrode pad portion 162 and the damstructure 163 may be formed to be integrated with each other. After thebackside pad 160 is formed, the mask pattern PR of FIG. 5G may beremoved and portions of a residual metal layer 161 on which the backsidepad 160 is not formed may be removed. The mask pattern PR may be removedby an ashing process, or the like. The portions of the metal layer 161may be removed by an etching process.

FIG. 6 is a cross-sectional view of a semiconductor package according toan example embodiment, FIGS. 7A and 7B are perspective views of selectedcomponents of FIG. 6 , FIGS. 8A and 8B are cross-sectional viewsillustrating modified examples of selected components in a portioncorresponding to region “A” of FIG. 6 . FIGS. 7A and 7B are perspectiveviews illustrating shapes of the electrode pad portion 162, the damstructure 163, and the through-via 140 in an example embodiment. FIGS.7A and 7B are perspective views illustrating different modified examplesof the shape of the dam structure 163, respectively.

Referring to FIG. 7A together with FIG. 6 , a semiconductor package 1000b may include a plurality of dam structures 163-1 and 163-2 sequentiallysurrounding the periphery of the through-via 140. For example, the damstructure 163 may include a first dam structure 163-1, disposed adjacentto the through-via 140, and a second dam structure 163-2 surrounding thefirst dam structure 163-1. In this case, a spacing distance between thefirst dam structure 163-1, closest to the through-via 140, and thethrough-via 140 in a horizontal direction (an X-axis direction) may bewithin the range of about 2 μm to about 5 μm. The first and second damstructures 163-1 and 163-2 may collectively doubly surround theperiphery of the through-via 140, and may more effectivelyprevent/impede cracking from propagating to the through-via 140.

Referring to FIG. 7B, the plurality of dam structures 163-1 and 163-2may include a plurality of separation walls, each discontinuouslysurrounding the through-via 140. For example, the first dam structure163-1 may include a plurality of first separation walls 163-1 a and163-1 b discontinuously surrounding the through-via 140, and the seconddam structure 163-2 may include a plurality of second separation walls163-2 a and 163-2 b discontinuously surrounding the through-via 140. Aplacement relationship between the plurality of first separation walls163-1 a and 163-1 b and the plurality of second separation walls 163-2 aand 163-2 b is not necessarily limited. However, when first spaces s1between the plurality of first separation walls 161-1 a and 163-1 b andsecond spaces s2 between the plurality of second separation walls 163-2a and 163-2 b are alternately disposed, propagation of cracking may beeffectively prevented/impeded. For example, the first spaces s1 mayalternate with the second spaces s2 around a circumference of thethrough-via 140 such that the first spaces s1 are offset from (e.g., donot horizontally overlap) the second spaces s2.

In addition, the plurality of dam structures 163-1 and 163-2 may have ashape in which the modified examples of FIGS. 7A and 7B are combinedwith each other. For example, among the plurality of dam structures163-1 and 163-2, at least one dam structure 163-1 or 163-2 may include aplurality of separation walls 163-1 a and 163-1 b or 163-2 a and 163-2 bdiscontinuously surrounding the through-via 140, as illustrated in FIG.7B, and the other dam structure 163-1 or 163-2 may have a ring shapecontinuously surrounding the through-via 140, as illustrated in FIG. 7A.

Hereinafter, another modified example of the plurality of dam structures163-1 and 163-2 will be described with reference to FIGS. 8A and 8B.FIG. 8A illustrates a region “Aa” corresponding to region “A” of FIG. 6to compare heights of the first dam structure 163-1 and the second damstructure 163-2 with each other. FIG. 8B illustrates a region “Ab”corresponding to region “A” of FIG. 6 compare heights of the first damstructure 163-1 and the second dam structure 163-2 with each other.

In a modified example, the plurality of dam structures 163-1 and 163-2may have different heights 163 h-1 and 163 h-2 in a vertical direction(a Z-axis direction). Among the plurality of dam structures 163-1 and163-2, a dam structure 163-1 or 163-2 having a relatively great heightmay have a height corresponding to 50% or more of the maximum thicknessof the passivation layer 114. However, the dam structure 163-1 or 163-2having a relatively small height may be less than the correspondingheight. The dam structure 163-1 or 163-2 having a relatively smallheight may serve to improve adhesion strength between the backside pad160 and the passivation layer 114.

Referring to FIG. 8A, the plurality of dam structures 163-1 and 163-2may have a height relatively decreased in a direction toward thethrough-via 140. For example, the first dam structure 163-1 may bedisposed to be closer to the through-via 140 than the second damstructure 163-2, and a height 163 h-1 of the first dam structure 163-1may be smaller than a height 163 h-2 of the second dam structure 163-2.The first dam structure 163-1, adjacent to the through-via 140, may havea spacing distance dl of about 2 μm or more to the through-via 140. Thesecond dam structure 163-2, having a relatively great height, may have aheight 163 h-2 corresponding to 50% to 80% of a maximum thickness of thepassivation layer 114.

Referring to FIG. 8B, the plurality of dam structures 163-1 and 163-2may have a height relatively increased in a direction toward thethrough-via 140. For example, the first dam structure 163-1 may bedisposed to be closer to the through-via 140 than the second damstructure 163-2, and a height 163 h-1 of the first dam structure 163-1may be greater than a height 163 h-2 of the second dam structure 163-2.The first dam structure 163-1, adjacent to the through-via 140, may havea spacing distance dl of about 2 μm or more to the through-via 140. Thefirst dam structure 163-1 having a relatively great height may have aheight 163 h-1 corresponding to 50% to 80% of a maximum thickness of thepassivation layer 114.

FIG. 9 is a cross-sectional view of a semiconductor package 1000 caccording to an example embodiment, and FIG. 10 is a perspective view ofselected components of FIG. 9 . FIG. 10 is a perspective viewillustrating a shape of an electrode pad portion 162, a dam structure163, and a through-via 140 in an example embodiment.

Referring to FIGS. 9 and 10 , in the semiconductor package 1000 c, thedam structure 163 may have a tapered shape in which a width of the damstructure 163 in a horizontal direction (an X-axis direction) isdecreased in a direction toward a first surface 111S1 of the damstructure 163. For example, a side surface 163S of the dam structure 163may have a predetermined slope with respect to an upper surface 162S ofthe electrode pad portion 162. During a process of etching thepassivation layer 114, the trench T1 may be formed to have an upperwidth greater than a lower width. Accordingly, the dam structure 163filling the trench T1 may have a side surface 163S tapered toward thefirst surface 111S1. As illustrated in FIG. 10 , the dam structure 163according to an example embodiment may have a shape surrounding thethrough-via 140, similarly to what is illustrated in FIG. 3A, other thanthe tapered shape. In some embodiments, the modified examples of FIGS.3B, 7A, and 7B may be combined with the dam structure 163 having atapered shape.

FIG. 11 is a cross-sectional view of a semiconductor package 1000 daccording to an example embodiment.

Referring to FIG. 11 , in an example embodiment, a through-via 140 maybe formed after a first circuit structure 120 is formed on asemiconductor substrate 110. Therefore, the semiconductor package 1000 dmay include the through-via 140 extending through the semiconductorsubstrate 110 and penetrating (i.e., extending into) the first circuitstructure 120. For example, the circuit structures 120 and 130 include afirst circuit structure 120 including a plurality of individual elements122 and disposed on a second surface 111S2, and a second structure 130including a second wiring structure 133, electrically connected to theplurality of individual devices 122, and disposed on the first circuitstructure 120. The through-via 140 may penetrate the semiconductorsubstrate 110, including a passivation layer 114 and a semiconductorlayer 111, and the first circuit structure 120 and may be electricallyconnected to a frontside pad 150 through the second wiring structure133.

FIG. 12 is a cross-sectional view of a semiconductor package 1000 eaccording to an example embodiment.

Referring to FIG. 12 , a through-via 140 may be formed after first andsecond circuit structures 120 and 130 are formed on a semiconductorsubstrate 110. Therefore, the semiconductor package 1000 e may includethrough-vias 140 penetrating through the semiconductor substrate 110 andfirst and second circuit structures 120 and 130. For example, thecircuit structures 120 and 130 include a first circuit structure 120,including a plurality of individual devices 122 and disposed on a secondsurface 111S2, and a second circuit structure 130 including a secondwiring structure 133, electrically connected to the plurality ofindividual devices 122, and disposed on the first circuit structure 120.The through-via 140 may penetrate a semiconductor substrate 110,including a passivation layer 114 and a semiconductor layer 111, andfirst and second circuit structures 120 and 130 to be electricallyconnected to a frontside pad 150 on the second circuit structure. Thefrontside pad 150 may be protected by a front insulating layer, and ametal bump and a UBM structure may be formed on the frontside pad 150.

FIG. 13 is a cross-sectional view of a semiconductor package 1000Aaccording to an example embodiment.

Referring to FIG. 13 , the semiconductor package 1000A may include abase chip 10 and a plurality of semiconductor chips 100, 200, 300, and400 stacked on the base chip 10 in a vertical direction (a Z-axisdirection). The semiconductor package 1000A may further include amolding member 20, a connection member 30 electrically connecting thebase chip 10 and the plurality of semiconductor chips 100, 200, 300, and400 to each other, and/or a non-conductive film layer 40 surrounding theconnection member 30 between the plurality of semiconductor chips 100,200, 300, and 400.

A width of the base chip 10 in a horizontal direction (an X-axisdirection) may be greater than a width of each of plurality ofsemiconductor chips 100, 200, 300, and 400 in the horizontal direction(the X-axis direction). This may result from a process in which theplurality of semiconductor chips 100, 200, 300, and 400 in a chip or diestate are sequentially stacked on the base chip 10 in a wafer state, andthe base chip 10 is then cut into individual chips.

The base chip 10 may include a base substrate 11, a circuit structure 12disposed on a lower surface of the base substrate 11, and a through-via14 penetrating through at least a portion of the base substrate 11 and aportion of the circuit structure 12, and a lower connection pad 15 andan upper connection pad 16, respectively disposed on a lower surface andan upper surface of the base chip 10. Unlike the plurality ofsemiconductor chips 100, 200, 300, and 400 stacked on the base chip 10,the base chip 10 may be a dummy semiconductor chip which does notinclude individual devices. The base chip 10 may be a buffer chipreceiving at least one of a control signal, a power supply signal, and aground signal for operating the plurality of semiconductor chips 100,200, 300, and 400 through a through-via 14, or a buffer chip receiving adata signal to be stored in the plurality of semiconductor chips 100,200, 300, and 400 from an external entity, or a buffer chip providingdata, stored in the plurality of semiconductor chips 100, 200, 300, and400, to an external entity.

The base substrate 11 may include, for example, a semiconductor layer,including silicon or the like, and a backside insulating layer disposedon the semiconductor layer. The backside insulating layer may include asilicon oxide layer, a silicon nitride layer, or a polymer layer, or thelike. The circuit structure 12 may include a silicon oxide layer, asilicon nitride layer, or an interlayer insulating layer, in which thesilicon oxide layer and the silicon nitride layer are combined, and awiring structure in the interlayer insulating layer. The through-via 14may penetrate the base substrate 11 and the circuit structure 12 toextend from an upper surface of the base chip 10 to a lower surface ofthe base chip 10. As illustrated in the drawing, the through-via 14 maypenetrate the circuit structure 12 to be directly connected to the lowerconnection pad 15. However, example embodiments are not limited thereto,and the through-via 14 may penetrate only the base substrate 11 and maybe electrically connected to the lower connection pad 15 through awiring structure of the circuit structure 12. The connection pads 15 and16 may include at least one of aluminum (Al), copper (Cu), nickel (Ni),tungsten (W), platinum (Pt), and gold (Au).

The molding member 20 may encapsulate the plurality of semiconductorchips 100, 200, 300, and 400 on the base chip 10. The molding member 20may cover side surfaces of the plurality of semiconductor chips 100,200, 300, and 400 to prevent/protect the plurality of semiconductorchips 100, 200, 300, and 400 from being exposed to an external entity.In the drawing, the molding member 20 is illustrated as covering anupper surface of an uppermost semiconductor chip 400. However, in otherembodiments, the molding member 20 may expose the upper surface of theuppermost semiconductor chip 400. The molding member 20 may include aninsulating resin, for example, an epoxy molding compound (EMC). Theconnection member 30 may electrically connect the semiconductor package1000A to a mounting substrate (for example, 50 of FIG. 14 ). Theconnection member 30 may include a conductive material, which is notlimited to a particular conductive material. The connection member 30may have a land, ball, or pin structure. The connection member 30 mayhave a multilayer structure including a copper pillar and a solder, or asingle-layer structure including a tin-silver (Sn—Ag) solder or copper.The non-conductive film layer 40 may include an adhesive resin, and maybond the plurality of semiconductor chips 100, 200, 300, and 400 to eachother. The adhesive resin may be a thermosetting resin and may include,for example, an epoxy resin.

The plurality of semiconductor chips 100, 200, 300, and 400 may have thesame technical features as described with reference to FIGS. 1 and 2 .For example, in an example embodiment, the semiconductor package 1000Amay include first to fourth semiconductor chips 100, 200, 300, and 400stacked in a vertical direction (a Z-axis direction). A first backsidepad 160, disposed on an upper surface of the first semiconductor chip100, and a second frontside pad 250, disposed on a lower surface of thesecond semiconductor chip 200, may be electrically connected to eachother through the connection member 30. Similarly, the base chip 10 andthe first semiconductor chip 100, the second semiconductor chip 200 andthe third semiconductor chip 300, and the third semiconductor chip 300and the fourth semiconductor chip 400 may be physically and electricallyconnected to each other. The first to fourth semiconductor chips 100,200, 300, and 400 may be memory chips and/or logic chips. The first tothird semiconductor chips 100, 200, and 300, connected to thesemiconductor chips disposed thereon through the connection member 30,may include backside pads 160, 260, and 360 having dam structures,respectively. In the drawing, through-vias 140, 240, and 340 areillustrated as being directly connected to the frontside pads 150, 250,and 350 and the backside pads 160, 260, and 360. However, it will bereadily understood, based on the foregoing, that the through-vias 140,240, and 340 may be electrically connected to the frontside pads 150,250, and 350 through a wiring structure of a circuit structure. Ascompared with FIGS. 1 and 2 , in FIG. 13 , the top and bottom of thefirst semiconductor chip 100 are inverted such that the frontside pad150 faces downwardly and the backside pad 160 faces upwardly. Inaddition, the first and second circuit structures 120 and 130 areillustrated as a single layer without an apparent boundary therebetween.

FIG. 14 is a cross-sectional view of a semiconductor package 1000Baccording to an example embodiment.

Referring to FIG. 14 , the semiconductor package 1000B may include amain semiconductor chip 500, attached to a mounting substrate 50, and aplurality of semiconductor chips 100, 200, 300, and 400 sequentiallystacked on the mounting substrate 50 to be adjacent to the mainsemiconductor chip 500.

The mounting board 50 may include a lower terminal 51 and an upperterminal 52, respectively disposed on a lower surface and an uppersurface, and a connection wiring 53 electrically connecting the lowerand upper terminals 51 and 52 to each other. The mounting substrate 50may be a substrate for a semiconductor package, such as a printedcircuit board (PCB), a ceramic substrate, and a tape wiring board, orthe like. For example, the mounting substrate 50 may be a siliconinterposer substrate having a through-silicon via (TSV).

The main semiconductor chip 500 may be a processing unit such as acentral processing unit (CPU) or a graphics processing unit (GPU). Themain semiconductor chip 500 may be a package for which a normaloperation has been verified, for example, a known good package (KGP).The main semiconductor chip 500 may be electrically connected to themounting substrate 50 through the connection member 30.

As previously described in FIG. 13 , the plurality of semiconductorchips 100, 200, 300, and 400 may be electrically connected to each otherthrough the through-vias 140, 240, 340 and the connection member 30. Theplurality of semiconductor chips 100, 200, 300, 400 may include avolatile memory chip such as a DRAM or an SRAM, or a nonvolatile memorychip such as a PRAM, an MRAM, a RRAM, or a flash memory. The pluralityof semiconductor chips 100, 200, 300, and 400 may be packaged in theform of the example embodiment illustrated in FIG. 13 to be attached tothe mounting substrate 50. Since the plurality of semiconductor chips100, 200, 300, and 400 have technical characteristics similar to thosedescribed in FIG. 13 , repeated detailed descriptions thereof will beomitted.

FIG. 15 is a cross-sectional view of a semiconductor package 1000Caccording to an example embodiment.

Referring to FIG. 15 , a semiconductor package 1000C may include a mainsemiconductor chip 500, attached to a mounting substrate 50, and aplurality of semiconductor chips 100, 200, 300, and 400 stacked on themain semiconductor chip 500 in a vertical direction (a Z-axisdirection).

The main semiconductor chip 500 may be a processing unit such as acentral processing unit (CPU) or a graphics processing unit (GPU). Themain semiconductor chip 500 may be a package for which a normaloperation has been verified, for example, a known good package (KGP). Inan example embodiment, the main semiconductor chip 500 may include asemiconductor substrate 541, a circuit structure 542, a through-via 544,and a lower terminal 545 and an upper connection terminal 546. Thecircuit structure 542 may include a wiring structure 543 connecting thethrough-via 544 and the lower connection terminal 545 to each other. Thecircuit structure 542 may include a plurality of individual deviceselectrically connected to the wiring structure 543, for example, aMOSFET, a system LSI, a MEMS, an active device, a passive device, andthe like. In the drawing, the through-via 544 is illustrated as beingconnected to the lower connection terminal 545 through the wiringstructure 543. However, the through-via 544 may penetrate the circuitstructure 542 to be electrically connected to the lower connectionterminal 545. Since the remaining semiconductor substrate 541, thethrough-vias 544, and the lower and upper connection terminals 545 and546 have characteristics similar to those of the base chip described inFIG. 13 , detailed descriptions thereof will be omitted.

The plurality of semiconductor chips 100, 200, 300, 400 may be stackedon the upper surface of the main semiconductor chip 500 in a verticaldirection (Z-axis direction), and may be electrically connected to themain substrate chip 500 and the mounting substrate 50 through the upperconnection terminal 546 and the through-via 544. The plurality ofsemiconductor chips 100, 200, 300, 400 may include a memory chip. Sincethe plurality of semiconductor chips 100, 200, 300, and 400 havetechnical characteristics similar to those described in FIG. 13 ,repeated detailed descriptions will be omitted.

As described above, a dam structure surrounding a through-via may beintroduced into a lower portion of a pad in contact with thethrough-via. Thus, a semiconductor package having improved reliabilityof a through-via may be provided.

While example embodiments have been shown and described above, it willbe apparent to those skilled in the art that modifications andvariations could be made without departing from the scope of the presentinvention as defined by the appended claims.

What is claimed is:
 1. A semiconductor package comprising: a plurality of semiconductor chips electrically connected to each other and stacked in a first direction, wherein at least one of the plurality of semiconductor chips includes a semiconductor substrate including a semiconductor layer having a first surface and a second surface that are opposite each other, a passivation layer on the first surface and having a third surface that is opposite the first surface, a circuit structure on the second surface, a frontside pad on the circuit structure, a backside pad on the third surface, and a through-via in the semiconductor substrate and extending between the second surface and the third surface to be electrically connected to the backside pad and the frontside pad, wherein the backside pad includes an electrode pad portion, on the third surface, and a dam structure protruding into the passivation layer toward the first surface of the semiconductor layer on one side of the electrode pad portion and surrounding a side surface of the through-via, wherein the dam structure is spaced apart from the side surface of the through-via, and wherein a height of the dam structure in the first direction into the passivation layer is less than a thickness of the passivation layer.
 2. The semiconductor package of claim 1, wherein the dam structure penetrates the third surface of the passivation layer, wherein a ratio of the height of the dam structure in the first direction to a maximum thickness of the passivation layer is within a range of about 0.5:1 to about 0.8:1, wherein the through-via and the dam structure are spaced apart from each other in a second direction that is perpendicular to the first direction, and wherein a spacing distance between the through-via and the dam structure is within a range of about 2 micrometers (μm) to about 5 μm.
 3. The semiconductor package of claim 1, wherein the backside pad further includes a metal layer between the dam structure and the passivation layer, between the electrode pad portion and the passivation layer, and between the electrode pad portion and the through-via.
 4. The semiconductor package of claim 3, wherein a thickness of the metal layer is within a range of about 0.05 micrometers (μm) to about 3 μm.
 5. The semiconductor package of claim 3, wherein the electrode pad portion and the dam structure include at least one of copper, nickel, gold, tantalum, or tungsten, and wherein the metal layer includes at least one of titanium, copper, cobalt, or tungsten.
 6. The semiconductor package of claim 1, wherein the dam structure has a ring shape continuously surrounding the through-via.
 7. The semiconductor package of claim 1, wherein the dam structure includes a plurality of separation walls discontinuously surrounding the through-via, and wherein a spacing distance between the plurality of separation walls is smaller than a spacing distance between the through-via and the plurality of separation walls.
 8. The semiconductor package of claim 1, wherein a width of the dam structure is tapered toward the first surface.
 9. The semiconductor package of claim 1, wherein the circuit structure includes a first circuit structure on the second surface and including a plurality of individual devices and a first wiring structure that is electrically connected to the plurality of individual devices, and a second circuit structure on the first circuit structure and including a second wiring structure electrically connected to the first wiring structure, and wherein the through-via is electrically connected to the frontside pad through the first and second wiring structures.
 10. The semiconductor package of claim 1, wherein the circuit structure includes a first circuit structure on the second surface and including a plurality of individual devices, and a second circuit structure on the first circuit structure and including a wiring structure electrically connected to the plurality of individual devices, and wherein the through-via extends through the semiconductor substrate and penetrates the first circuit structure and is electrically connected to the frontside pad through the wiring structure.
 11. The semiconductor package of claim 1, wherein the circuit structure includes a first circuit structure on the second surface and including a plurality of individual devices, and a second circuit structure on the first circuit structure, and wherein the through-via penetrates the semiconductor substrate and the first and second circuit structures to be electrically connected to the frontside pad.
 12. The semiconductor package of claim 1, wherein the passivation layer includes at least one of silicon oxide or silicon nitride.
 13. The semiconductor package of claim 12, wherein a thickness of the passivation layer is within a range of about 2 micrometers (μm) to about 5 μm.
 14. The semiconductor package of claim 1, wherein the passivation layer and the first surface of the semiconductor substrate define a planar interface extending from the through-via to an edge of the backside pad.
 15. The semiconductor package of claim 1, wherein the dam structure includes a first dam structure, adjacent to the through-via, and a second dam structure surrounding the first dam structure, and wherein a spacing distance between the first dam structure and the through-via in a second direction, perpendicular to the first direction, is within a range of about 2 micrometers (μm) to about 5 μm.
 16. A semiconductor package comprising: a plurality of semiconductor chips electrically connected to each other and stacked in a first direction, wherein at least one of the plurality of semiconductor chips includes, a semiconductor substrate including a semiconductor layer having a first surface and a second surface that are opposite each other, a passivation layer on the first surface and having a third surface that is opposite the first surface, a circuit structure on the second surface, a frontside pad on the circuit structure, a backside pad on the third surface, and a through-via in the semiconductor substrate and extending between the second surface and the third surface to be electrically connected to the backside pad and the frontside pad, wherein the backside pad includes an electrode pad portion, on the third surface, and a dam structure protruding toward the first surface on one side of the electrode pad portion and surrounding a side surface of the through-via, wherein the dam structure is spaced apart from the side surface of the through-via, wherein the dam structure includes a first dam structure, adjacent to the through-via, and a second dam structure surrounding the first dam structure, and wherein a spacing distance between the first dam structure and the through-via in a second direction, perpendicular to the first direction, is within a range of about 2 micrometers (μm) to about 5 μm.
 17. The semiconductor package of claim 16, wherein one of the first and second dam structures includes a plurality of separation walls discontinuously surrounding the through-via, and wherein the other one of the first and second dam structures has a ring shape continuously surrounding the through-via.
 18. The semiconductor package of claim 16, wherein the first dam structure includes a plurality of first separation walls discontinuously surrounding the through-via, wherein the second dam structure includes a plurality of second separation walls discontinuously surrounding the through-via, and wherein a first space between the plurality of first separation walls and a second space between the plurality of second separation walls are offset from each other.
 19. The semiconductor package of claim 16, wherein a height of the first dam structure in the first direction and a height of the second dam structure in the first direction are different from each other.
 20. A semiconductor package comprising: a first semiconductor chip including a semiconductor layer having a first surface and a second surface that are opposite each other, a passivation layer having a third surface that is opposite the first surface and a trench that is in the third surface, a through-via penetrating the semiconductor layer and the passivation layer, and a backside pad on the third surface and electrically connected to the through-via; a second semiconductor chip including a frontside pad and on the first semiconductor chip such that the frontside pad faces the backside pad; and a connection bump electrically connecting the backside pad and the frontside pad to each other, wherein the trench is spaced apart from the through-via in a first direction horizontal to the third surface, wherein a spacing distance between the trench and the through-via is within a range of about 2 micrometers (μm) to about 5 μm, wherein a ratio of a depth of the trench in a second direction, perpendicular to the third surface, to a maximum distance between the third surface and the first surface is about 0.5:1 to about 0.8:1, and wherein the backside pad includes a dam structure in the trench. 